Process of desiccating milk.



U. ELLIS.

PROCESS OF DESIGCATING MILK.

\Xvwwaws.

APPLICATION FILED D3016, 1909. Y

Patented Aug. 1, 1911..

CABLETON ELLIS, or MONTCLAIB, NEW JERSEY, es srenon. r nLLrs-rostmn comrm,

A CORPORATION or NEW' JERSEY.

PROCESS or nns rcca'rrne MILK.

Mont'clai'r,in the county of Essex and tate 'of NewjJersey, have invented certain new and" useful Improvements in Processes of Desiccating Milk, of which the following is a specification.

This invention relates to processes of desiccating milk, and relates particularly to: 'a method involving the drying of milk by:

a jet of air preferably artificially dried.

In' view of the'impossibility of keeping: milk for any substantial length of time; without the use of preservatives,- manyl 'efiorts have' been made to produce a dried; milk'which would retain all the character- 'istics of the original milk as regards solu-; -bility and ass1milability, andwhich, being free from moisture, would'retain its qual ties for an indefinite length of time. Ord1- 'nary milk cannot be kept for more than ai 'few days without the use of preservatwes; such as sodium benzoate, salicylate, borax, 'formaldehyde, and the like, all of which are more or less injurious to the human system if taken periodically in small quant1t1es.-

The expense moreover, of keeping ordinary milk without the use of preservatives 1s very great' With certified milk, which is the only unmodified milk that is regarded as 3 ment, results in an increase 1n the content fairly safe 'toconsume, so much care has to be devoted" to the proper keeping of the milk that it becomes very expensive. Aboard steamships, for example, it isimpossible to carry milk or cream except for very short voyages, without the use of preservatives. I r

- Another very important consideration, especially in the neighborhood of large cities', is the great bulk or weight of flu1d milk in comparison with its actual nutritive value. Ordinary 'milk carries only 10 to '12 per cent. of solid material,,the balance being water. The cost of shipping milk in this'form to meet the requirements of a large city, is'very great, and the advantages of a"dr'iedmilk, having, when dissolved in water,'fall the qualities of .fresh milk, will be evident. f f a.

' Prior elior ts toproduce a dried milk or product retaining the natural qualities ofinilk ina large measure, have been devoid at satisfactory r sults mainly because of the conduct of the processes'involved at temacaw ot'Lett ers mat.

, Application tiled December 16, 1809. ,Serial 110 533375.

Patented Aug. 1, 1911.

peratures'itoo high to allow of the proper deslccati'on of the milk without undergoing chemical changes. For example, in earlier processes, the temperatures were so hi h that the milk sugar, which is present to t e extent of 4 or 5 per cent. in milk, and is in fact, the constituentpresent in largest amount, underwent changes of a caramelizmg character, discoloring the milk and 'changmg ,its flavor. Although the operations in many cases .apparently were conducted at temperature seemingly below the "caramellzlng. point, namely 215 degrees Fahrenheit, yet because of the action of the walls of the evaporating vessel which probablywere superheated, the caramelizing actlon referred to often resulted; Furthermore, the various processes, which involved much agitation or treatment in vessels on 'drums and'the like, caused the rupturing of the fat globules resulting in the agglomerat1on of the oil into masses which became rancid on'exposure. The maintenance of the fat in'its natural globular condition, is

apparently essential to its preservation in dried form, for if the fat globules rupture and the fat particles coalesce, rancidity and change of flavor ensues on storage. Furthermore, the slow drying of milk accompanied by exposure to rather high temperatures and considerable mechanical treatofllactic acid, and as the milk concentrates, the proportionate amount of lactic acid very rapidly increases, resulting in an action on the casein which is highly detrimental. Under such conditions of high lactic acid content, casein in a verylarge measure loses" its solubility and coagulates to form a product which is not readily digested. Various endeavors to neutralize the lactic acid by the addition of soda, lime, etc, in some 'measure overcomes this difliculty, but the soapy taste resulting in such instances from such neutralizing additions. makes their use objectionable. Furthermore; under the conditions of concentration as heretofore largely practiced, the albumin of the milk. which is a very. important food element, is rendered insoluble and extremely diflicult of digestion. This appears to be due to the jointaction of lactic acid and heat, although suflicientheat alone, will of course, cause the coagulation .of albumin without the presence of the acid. The allion than the casein. It appears to be a complex mixture of albumrnous material.

extremely sensitive to the action of heat, and not always to be counted on as undergoing the same changes, when apparently desiccated under the same conditions. Most processes of drying milk, furthermore, are such as to render it necessary to leave iuthe milk from to 3 M4 per cent. of the moisture; On storage, deleterious changes may take place in the character of milk containing moisture ofsuch amount. This 15 especially true in the warmer climates. More particularly, reactions involving the decomposition of the albumin are liable to occur.

It'is the object of my invention to desiccate milk without caramelization of milk sugar or rupturing of the globules of fat, and with the processes conducted in such a manner that the lactic acid does not affect the solubility of the casein or albumin. For this purpose I concentrate ordinary milk in a. vacuum pan, for example, until it is reduced to a fairly thick mass containing 40 to per cent. ofvwater or thereabout, and then atomize this milk with air, preferably well dried, so as to dry the atomized milk without contact with metallic surfaces during thelatter stages of the drying. The first concentration in the vacuum pan may be carried on without great difficulty up to the degree of concentration referred to. Beyond that, coagulation of the casein and albumin is liable to occur, subsequently followed by caramelization of the milk sugar. Before this occurs, however, the milk is removed from the vacuum pan and subjected to the atomizing and desiccating action referred to. By the use of dry air, which may or may not be warmed, according to circumstances, a milk may be produced which has undergone no chemical change in drying and in which the lactic acid content is practically no'higher relatively speaking, than that in normal milk; and furthermore, the particles of the dried milk are in such form as to be particularly soluble in water, so that by the mere addition to the dried milk of a suitable quantity of water, a fluid is immediately produced having the desirable characteristics of normal fresh milk. Under the conditions of operation, it is obvious that the product may be made comparatively freefrom all injurious bacteria, so that the fluid milk made from the desiccated product may be taken at any time without fear of contamination.

By reference to the accompanying dia grammatic drawings, it will be seen in what manner I carry out the process in its preferred embodiment; wherein Figure 1 shows a general plan of the apparatus with the evaporator shown in seccold air.

tion, and Fig. 2 shows a section of the evaporator at a point where air jets enter it and also shows the means for the admission of In Fig. 1, 1 is a double-bottom tank having the receptacle 2 containing fresh fluid milk. 3 is a valve in the pipe 4, connecting the receptacle 2 ,with the vacuum pan 5. This pan may be of the usual type of vacuum evaporator, preferably that known as the multiple effect. The pipe 6 leads from the vacuum pan to the rotary evaporator 8. This pipe 6 is supplied with the valve 7. 9 is a blower for supplying air under pressure. The outlet pipe 10 of this blower connects with the bottom section 12, of the pan 1, pipe 10 being fitted with the valve 11. The lower space or section of the pan 1, forms a jacket around the receptacle 2. An outlet pipe 18 leadsv from this lower space 12 to the heater 14. The pipe 15 leads from the heater 14 to the rotary evaporator. In this pipe is the valve 16. The outlets into the evaporator are 8, 18 and 20, and the two last named outlets are controlled by the valves 21 and 22. These outlets for the pipe 15 or inlets for evaporator 19, especially those at 18 and 20 are arranged to admit air more or less peripherally of the evaporator. This evaporator is shown of a cylindrical type, so that the auxiliary jets of air may be introduced tangentially, thereby causing the drying milk to travel. in a circular or spiral path. An outlet pipe 23 leads from the evaporator 19, and "at 24 is fitted with a discharge outlet controlled by the valve 25. The connecting pipe 26, controlled by the valve 27, leads to the refrigerating apparatus 30, having the inlet and outlet pipes 31 and 32, and water discharge pipe 33. An air inlet pipe 28 controlled by the valve 29 is placed in pipe 26 between the refrigerating apparatus 30 and the valve 27. From the refrigerating apparatus, a pipe 34 controlled by the valve 35, leads to the blower 9. In this pipe is situated the inlet pipe 86 controlled by the valve 37. In the lower part of the evaporator 19, is the discharge outlet 42, connected with the drying chamber 40, which carries the cenveyer 43. The pipe 38 connecting through the pipe 10 with the blower 9 and valved at 39, enters the drying chamber 40, which is fitted with the outlet 41. 44 isa. hopper and chute fitted with the gate 45.

In the operation of my process, fresh milk is placed in pan 2, and is allowed to discharge through the pipe 4 into the vacuum pan 5. From there it is takento the evaporator 19, and enters the atomizer 8. Air

which has passed through the refrigerating apparatus 30, is forced by the blower 9, around the pan 2, through the jacketed space 12, thereby cooling the contents of the pan 2, and preventing bacterial decomalong the walls of the evaporator 19 and position of the milk while in storage. vFrom thence, the air passes through the heating device 14 andreaches the atomizer 8 in a warm or hot condition. It there meets with a stream 'of milk coming from the vacuum pan 5 and mingles with it, absorbing the moisture from the finely divided particles of milk, reducing them to a slightly plastic or somewhat pulverulent condition. This jet or current of air and finely divided milk travels peripherally would impinge upon the walls and there adhere or clog except for the act1on of the jets entering at 18 and 20, which d scharg- -ing additional quantities of dry air, fend the current of dry milk from the walls of,

the evaporator and exert a desiccating action at a very moderate temperature, so

'that the milk is rapidly dried without subjecting it to temperatures resulting in decomposition from coagulatron. The drled milk is withdrawn fromthe bottom of the evaporator, and if it contains more than 1 'or 2 per cent. of moisture or thereabout is preferably allowed to traverse the drying chamber 40, along the conveyer 48, where it is subjected to cooled or dried air, or dry air at temperatures scarcely elevated above atmospheric. est stages ,ofthe drylng of milk when the lactic acid content has increased' in concentration to approximately the maximum, that the obscure changes most rapidly p'rogress which renderthe casein and. albumin insoluble, it is desirable to complete the drying at substantially atmospheric temperature by means of air from which the major portion of the normal moisture has been removed'by refrigeration or otherwise. It is of course, feasible to shunt a portion of the heated air from the pipe 15 into the pipe 38, and thus, if desired, raise the temperature of the drying current in drying chamber 40, to a temperature slightly' higher than normal atmospheric temperatures. It is possible by means of the heater 14, to maintain the temperature of the air passing from the pipe 15 into'the evaporator at any desired temperature, and it may be entered through the inlet'8 at a rather elevated temperature, as at that point the milk carries the maximum amount of water. The air entering at 18 may be at' a lower temperature, and that at 20 still further reduced and finally, preferably'in the drying chamber, the air should be atmospheric temperature, or even less. In this manner, decomposition of the milk is prevented and a composition of natural solubility secured. The successive reduction in temperature of the air jets, at 8,.

18 and 20 respectively maybe securedjby allowing the pipes to be unjacketed so that the 'radlation losses effect the cooling. Or

.sirableto have the apparatus sufficiently Inasmuch as it is in the latthis may be accomplished as -shown in Fig. I

2, where cold air is entered in regulated amounts by means of the cold air inlet pipes Nos. 46 and 47. Inasmuch as the air which passes repeatedly over the milk inthe drying process, apparently becomes less capable of oxidizing the particles of milk, the apparatus is preferably arranged tocarry the air or'a portionof it in a cyclic path, leaving the evaporator, it may pass through the pipe 26, refrigerator, to be there divestedof its moisture and sent through the evaporator or drying chamber, or both, at will. The inlet pipe 28 is provided so that mixtures of the cyclic airand'ordinary air may be made; or, if desired, ordinary air alone employed. At 36, an air pipe is arrange-d to admit ordinary refrigerated or ,undried air when the" conditions of operation warrant its use. j

Since the process may be applied to the drying of malt extracts (alone or in conjunction with milk) and the like,-it is deflexible to allow of operating with various materials under various conditions.

While the pan 2 surrounded by the cooling jacket 12 is not essential, it is a desirable element because of the ability to store large quantities of the milk and maintain cost, asthe air going fromtheblower 9, if refrigerated, serves to cool the milk and at' the same time, theheating required in heating chamber 14, is not as great. If it be desired to introduce the air into the evaporator 19 at a very low temperature,-the heating chamber 14 may be cutout and the air passed directly-from the blower to the evaporator.

The whole operation is designed to be. conducted in a continuous manner, in order to avoid the cost attendant on the handling of a product as bulky as milk by an intersive increment in .the content of the lactic acid," by which method, in conjunction with the continuous process of handling the tures of those heretofore preparedby those processes which fail to take cognizance of at a low temperature without additional product, a desiccated milk is secured which 1 is entirely free from the objectionable feathe chemical deteriorations and change in" a jet of artificially dried and warmed air under pressure, whereby a current of air carrying subdivlded particles of m1lk un- (lei-going desiccation, is produced and in introducing into said current, successive jets of air to substantially complete the drying of said milk particles. r

2. The process of desiccating milk which consists in partiallyconcentrating milk under diminished atmospheric pressure, in

mingling said partially concentrated milk' with a pressure jet of dried and heated air to produce a current in which the particles of milk undergoing desiccation are therein suspended, and in successively introducing into sald current, ets of a1r at successlvely lower temperatures to produce a pulveru lent milk product substantially free from moisture, said jets of air being introduced at such temperatures that the drying of themilk is conducted at successively lower temperatures proportionate to. the increase in concentration of the lactic acid content of the milk particles.

3. The process of desiccating milk which consists in subjecting milk to partial concentration under diminished pressure, in mingling said .partially concentrated milk scope? with artificially dried and heated air under pressure, in separating said milk when substantially dry fromsaid air, in passing over the substantially dried roduct, a current of artificially dried cold an to remove the last traces of moisture and in collecting "there:

sulting dried product.

4. The process of desiccating milk which consists in subjecting fresh milk to partial concentration under diminished pressure, mingling said partially concentrated milk with dried and heated air, under atomizing conditions, in allowing said air to act upon said milk until the moisture is substantially removed, in passing a current of cold artificially dried air over. the resulting driedmilk to remove the last traces of moisture and in removing a portion of the air used for drying said milk, refrigerating said air to remove the moisture thereof, and in min: gling said air with additional quantities of partially concentrated milk. 1

5. The process of desiccating milk, which consists in partially. concentrating fresh "milk under diminished admospheric pressure, mingling said partially concentrated -milk with a jet of heatedair to form a stream of drying milk suspended in a current of air, in causing said stream to travel in a spiral path, in successively introducing into said stream a plurality of air jets and in collecting the milk in a pulverulent c011- dition, substantially free from moisture.

In testimony whereof I have atlixed my signature presence of two witnesses.

GARLETON ELLIS.

Witnesses NATHANIEL L. FOSTER, JAMES B. ELLOTT. 

